Sometimes, a simple idea can make you a whole lot of money. That's exactly what happened to Emily Jump, a 25-year-old marketing coordinator who hit a gold mine with her side hustle. While working at a dental office in Columbus, Ohio, she noticed that their schedule was constantly booked with clients looking to get teeth whitening or veneers, even though COVID-19 was ravaging the state. Given that mask mandates were being enforced, she wondered why people were still seeking cosmetic services even though their smiles would be hidden.

That's when she started thinking about the other aspects of the face: the eyes and brows. Those would not be covered by a mask, and she knew that there was indeed a market for beauty services regarding those features. So she did some research into microblading, which is a semi-permanent brow enhancement procedure that involves using small strokes to tattoo the eyebrows. On her off days, Jump would attend microblading classes and she practiced for several hours a day.

Eventually, she turned that hobby into a full-fledged business, and in no time, she was able to generate an income of at least $7,200 per month; all while still working at the dental office where she had an annual salary of $34,500.

"In June this year, after three months of juggling both jobs, I decided to quit my day job and turn my microblading side hustle into a full-time business," she explained to CNBC. "I named it Columbus Cosmetic Ink. Today, I bring in about $8,750 per month in sales, including tips—triple what I earned at the dental office job."

When she decided that she wanted to take her brow business seriously, she came up with a business plan. She admitted that it wasn't perfect, but that even with a lack of a business degree, she was able to draft one up and use it to help her stay on top of important components such as customer demand, expenses, financial expenses, and marketing.

She also worked for free for a short while, just so she could build her portfolio and start building a clientele. "I used Nextdoor, an app for neighborhoods where you can share local tips, to start marketing my services. I posted 'Models Wanted: Free Microblading,' and ended up getting a lot of attention and interest."

Perhaps the one word of caution Jump has for any entrepreneur is that starting a business will mean necessary sacrifices will have to be made. When she was alternating between her full-time job and her side hustle, she mentions that she was working as many as 70 hours per week. She had to sacrifice her social life, sleep, lunch breaks, and leisure time.

But for a couple extra thousand dollars a month, such sacrifices may be well worth making.